1. Field of the Invention
The present invention relates to an image-forming apparatus, a network-type image-forming apparatus and method therefor for discharging to a stacker a sheet on which an image has been formed by an image-forming unit, and more particularly, to an image-forming apparatus, a network-type image-forming apparatus and method therefor for controlling the attitude of a discharged sheet in a stacker.
2. Description of the Related Art
A page printer, such as an electro-photographic printer, is capable of high-speed printing, and is being used widely as a computer output device. In line with the promotion of networking of information processing equipment in recent years, often a single printer, such as an electro-photographic printer, is connected to a plurality of personal computers (PCs) being no exception to this rule. Further, in accordance with the faster processing capabilities of printers, instead of printing by copying machine a required number of copies of a printed sheet that was printed on a printer, utilization environments in which a required number of copies is printed by printer are on the increase.
Consequently, there is need for a contrivance for using a printer either in an environment, wherein a plurality of number of copies are printed at one time, or in an environment, wherein a single printer is used by a plurality of users.
With a conventional printer, after printing, the paper thereof is stacked straight. Therefore, when a plurality of users successively use a printer, or a plurality of number of copies are printed, the printed matter, which should be sorted, is piled one on top of the other.
Because it is not possible to change the attitude of a sheet with a single stacker like this, the following methods are known as methods for sorting by user and by number of copies.
(1) A multi-bin unit or plurality of stackers is provided either separately from or integrated with a printer, and sorting is performed by changing the storage location of the discharged sheets in the unit or the stacker.
(2) A post-sheet-processing device is disposed on a copying machine, and sorting is performed by controlling the attitude of discharged sheets of paper via the post-processing device (For example, Japanese Patent Laid-open No. H11-217153).
(3) When the same is done using a printer that does not have a multi-bin or plurality of stackers, two or more paper feeding cassettes (units) are provided, the same medium is set longitudinally and transversely, respectively, the cassettes are switched for each job, and sheets of paper are stacked alternately longitudinally and transversely.
However, the problem with these methods is that options, such as a multi-bin, post-processing device, or second cassette must be added, increasing device volume and running counter to efforts to make devices smaller.
Further, the problem is that optional products, unlike general-purpose mass-produced printers, are not produced in volume, thus increasing implementation costs.
Therefore, it is an object of the present invention to provide an image-forming apparatus, network-type image-forming apparatus and method therefor for controlling inside an image-forming apparatus the attitude of a sheet for sorting, and for preventing a device from becoming large.
Further, it is another object of the present invention to provide an image-forming apparatus, network-type image-forming apparatus and method therefor for controlling the attitude of a discharged sheet without providing option devices, and for lowering implementation costs.
To achieve these objects, an image-forming apparatus and a network-type image-forming apparatus of the present invention comprise; an image-forming unit for forming an image on a sheet, a stacker for storing a sheet on which an image has been formed, a discharging unit for discharging to the above-mentioned stacker via a plurality of independently driven discharging rollers a sheet on which an image has been formed by an image-forming unit, and a controller for controlling the driving of the above-mentioned discharging rollers. The controller selectively executes an attitude control mode, whereby the driving of the discharging rollers of the one side of the above-mentioned plurality of discharging rollers is stopped for a predetermined period of time part way through the discharging of the above-mentioned sheet by the above-mentioned plurality of discharging rollers, and thereafter, the driving of the above-mentioned discharging rollers of the one side is restarted, and a normal mode, whereby the above-mentioned sheet is discharged by driving both sides of the above-mentioned plurality of discharging rollers.
An image-forming method of the present invention comprises the steps of image-forming for forming an image on a sheet, discharging for discharging to a stacker via an independently-driven plurality of discharging rollers a sheet on which an image has been formed by the above-mentioned image-forming unit, and controlling for controlling the driving of the above-mentioned discharging rollers. The controlling step selectively executes an attitude control mode, whereby the driving of the discharging rollers of the one side of the above-mentioned plurality of discharging rollers is stopped for a predetermined period of time part way through the discharging of the above-mentioned sheet by the above-mentioned plurality of discharging rollers, and thereafter, the driving of the above-mentioned discharging rollers of the one side is restarted, and a normal mode, whereby the above-mentioned sheet is discharged by driving both sides of the above-mentioned plurality of discharging rollers.
Because the present invention is constituted so as to independently drive a plurality of discharging rollers, which discharge a sheet to a stacker, and such that the driving of this plurality of discharging rollers differs for a normal mode and an attitude control mode, it is possible to sort printed matter on top of a stacker with one paper feeding means and a single stacker without providing optional equipment. Further, because the driving of the discharging rollers of the one side is stopped for a predetermined period of time during attitude control, and a sheet is rotated using this roller as a pivot point, it becomes possible to perform stacking easily and stably even for multiple types of media for which the stacking angle was unstable with a method, whereby paper discharging is performed by differing the speed of the right and left rollers.
Further, in the present invention, in forming an image on the above-mentioned sheet for a plurality of numbers of copies, preferably the controller alternately switches the discharge control of the above-mentioned sheet of each of the above-mentioned numbers of copies between the above-mentioned attitude control mode and the above-mentioned normal mode for each of the above-mentioned numbers of copies to sort the image-formed printed matter on the stacker. Therefore, it is possible to achieve on a stacker the sorting of a plurality of numbers of copies of printed matter.
Furthermore, in the present invention, in forming an image on the above-mentioned sheet for a plurality of jobs, preferably the controller alternately switches the discharge control of the above-mentioned sheet of each of the above-mentioned jobs between the above-mentioned attitude control mode and the above-mentioned normal mode for each of the above-mentioned jobs to sort the above-mentioned image-formed printed matter on the above-mentioned stacker. Therefore, it is possible to achieve on a stacker the sorting of printed matter by job.